Conventional automatic duplex documents sheet handling and imaging systems have increased the effective imaging, scanning, or copying rate for both sides of sets of duplex documents. Such conventional automatic document handlers automatically sequentially feed and image a set or job of plural duplex (two-sided) document sheets, while at the same, these conventional document handlers are capable of feeding and copying simplex documents (one-side). For example, a conventional automatic document feeder, which is particularly suited for imaging the documents electronically (digitally) while the document is moved past such an imaging station with a constant velocity transport, allows for a more compact and faster imaging document handler as compared to document handlers which place the document on a full size platen and hold the document stationary while it is scanned by a moving scanner.
A particular difficulty in duplex document handling for electronic imaging is the desirability of having only a single electronic imaging station. However, that requires inverting or turning over each duplex document after imaging one side thereof in order to image the other side of the duplex document, and/or reorienting the documents for collated restacking. In conventional duplex document handling systems, the inversion requirement required several time delays in which no document side (page) imaging is being accomplished, thus effectively reducing the effective imaging or duplex document copying rate of the overall system. Thus, it is desirable to provide a duplex document handling system with improved productivity or throughput rate for electronic document scanners.
Another problem with conventional automatic duplex documents sheet handling systems is the additional requirement of inverting the document twice in the overall document path in order to return the document sheet to the exit tray in the original order and be properly collated. As is well known, if documents are fed in forward serial order (1 to N page order) and are sequentially stacked on top of one another as the documents exit the system, regardless of whether the output tray is a separate tray or the original input tray, the document sheets must be stacked “face down” in order to remain collated and in proper order when fed in such forward or 1 to N page order. Otherwise, the sheets must be undesirably manually reordered after imaging.
Furthermore, conventional automatic duplex documents sheet handling systems have been constructed such that the input tray and the output tray of a document handler are in a vertical relationship to provide a more compact overall configuration and allow the document inversion path to be compactly interposed between the overlying upper and lower trays. In the conventional automatic duplex documents sheet handling systems having a vertical relationship, simplex documents are restacked face down and collated if the simplex documents are fed from the top of a face up stack in the input tray. However, this handling of a duplex document present a problem in that the duplex documents must be inverted a second time between the imaging of one side and the imaging of the other side of the duplex document. Moreover, a third inversion of the duplex document is required in order to allow the duplex document to be restacked properly collated in the output tray. This third inversion causes a productivity loss, especially where the inversion is done utilizing the path through the imaging station, preventing the imaging of any document in that time period.
Another example of a conventional duplex scanning system exposes both sides of a document while the document is moved along a continuous velocity path. Conventionally, two scan illumination stations are used, one for each side of the document, with the scanned images of the first side and the second side following two optical paths but imaged via the same imaging plane. Such two scan illumination stations require a moving mirror or a moving lens to bring projected images onto a common imaging plane. Optical components in motion can create optical misalignments and vibrations. Such motion is also time consuming and requires precision mechanisms which may be costly to manufacture.
A further example of a conventional duplex scanning system uses two raster image scanners in separate imaging planes to image both sides of the document to eliminate the need for a moving mirror or a moving lens. This conventional approach increases the manufacturing cost of the imaging system.
A still further example of a conventional duplex scanning system provide a system with two exposure stations, one for each side of the paper, but only one raster image scanner. At each imaging station, the document to be imaged passes over the top of a platen at each imaging station and light reflected from the side facing the platen is captured by a lens. The lens for the first imaging station captures the image of the first side reflected through the platen of the first imaging station. The lens array for the second imaging station captures the image of the second side reflected through the platen of the second imaging station and then transmits that the image to the raster image scanner through the platen of the first imaging station.
Therefore, it is desirable to provide a duplex document scanning system with improved productivity or throughput rate for electronic document scanners. Furthermore, it is desirable to provide a duplex document scanning system with a document path having a minimum number of inversions. Also, it is desirable to provide a duplex document scanning system with a document path that restacks the documents in a proper order. Moreover, it is desirable to provide a duplex document scanning system that utilizes only one raster image scanner, one illumination source, and one pass through the document path.
An automatic document handling system includes a first imaging area; a light source located in proximity to the first imaging area; a raster imaging scanning system located in proximity to the first imaging area; a semicircular document path, located in proximity to the first imaging area, having an entrance and an exit; a second imaging area located in proximity to the exit of the semicircular document path; and a bi-directional fiber optic element located between the first and second imaging areas. The bi-directional fiber optic element transmits light from the light source to the second imaging area and transmits light reflected from the second imaging area to the first imaging area.
An automatic document handling system includes a first imaging area; a light source located in proximity to the first imaging area; a raster imaging scanning system located in proximity to the first imaging area; a semicircular document path, located in proximity to the first imaging area, having an entrance and an exit; a second imaging area located in proximity to the exit of the semicircular document path; a first fiber optic element located between the first and second imaging areas; and a second fiber optic element located between the first and second imaging areas. The first fiber optic element transmits light from the light source to the second imaging area and transmits light reflected from the second imaging area to the first imaging area.
An automatic document handling system includes an imaging area; a light source located in proximity to the imaging area; a raster imaging scanning system located in proximity to the imaging area; and a looped document path, located in proximity to the imaging area, having an entrance and an exit. The exit of the looped document path is positioned such that an exiting document is placed upon the imaging area a second time.